01-setup-express-ts.md

Node.js Express with TypeScript

This guide helps you set up a Node.js Express project with TypeScript from scratch.

Prerequisites

• Node.js installed (Recommended: Latest LTS version)
• npm (comes with Node.js)

Step 1: Initialize the Project

Run the following command to create a package.json file:

npm init -y

Step 2: Install Dependencies

Install Express and its required packages:

npm install express

Install TypeScript and development dependencies:

npm install --save-dev typescript ts-node @types/node @types/express

Install DotEnv for environment variables from a .env file

npm install dotenv

Step 3: Initialize TypeScript

Run the following command to generate a tsconfig.json file:

npx tsc --init

Modify tsconfig.json with the following settings:

{
  "compilerOptions": {
    "target": "ES6",
    "module": "CommonJS",
    "outDir": "./dist",
    "rootDir": "./src",
    "strict": true
  }
}

Step 4: Create an Express Server

Create a src/index.ts file and add:

import express from "express";

const app = express();

Step 5: Run the Project

Use ts-node to run the TypeScript server:

npx ts-node src/index.ts

Alternatively, compile and run:

npx tsc
node dist/index.js

Step 6: Add a Start Script

Modify package.json to add the following script:

"scripts": {
  "dev": "ts-node src/index.ts",
  "build": "tsc",
  "start": "node dist/index.js"
}

Now, you can start the server in development mode using:

npm run dev

Step 7: Set Up Testing

Run the following command to install Jest and required packages:

npm install --save-dev jest ts-jest @types/jest supertest @types/supertest

Configure Jest

Initialize Jest with TypeScript support:

npx ts-jest config:init

Run Tests

npm test

Nice to know

1. Express: A minimal and flexible web application framework for Node.js.
2. TypeScript: A superset of JavaScript that adds static typing and advanced language features.
3. ts-node: A TypeScript execution environment for Node.js.
4. @types/express: TypeScript declaration files for Express.

Conclusion

You have successfully set up an Express.js server with TypeScript. 🎉